First off how large is your greenhouse? Second how much are you willing to spend? Heat storage is the key right up there with cutting down waste and loss.
We’ve been using solar hot water for years now even in winter. If I had your problem and had a little money to spend here’s what I would do. I would use solar electric to heat water in large well insulated tank(s). I would then pipe the water in to the floor of my beds through PEX pipe. Thus heating from the root zone upward which will require the least heat with the most gain from that heat. I wouldn’t take the bed temps above 70-72 though. This would basically be a one time expense. Sure parts wear out and such but no ongoing labor or bill. I’ve bought 48 volt DC elements from Ebay with good luck they even have inline thermostats if you want to go that route. But I think you will need to worry more about the bed temp overall more than the water temp in the storage tank(s).
Communities
Report
There was a problem reporting this post.
Block Member?
Please confirm you want to block this member.
You will no longer be able to:
See blocked member's posts
Mention this member in posts
Invite this member to groups
Message this member
Add this member as a connection
Please note:
This action will also remove this member from your connections and send a report to the site admin.
Please allow a few minutes for this process to complete.